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<A NAME="X-REF298726755"></A><h1>About inheritance </h1>
<A NAME="TI3237"></A><p>One of the most powerful features of PowerBuilder is inheritance.
It enables you to build windows, user objects, and menus that derive
from existing objects.</p>
<A NAME="TI3238"></A><p>Using inheritance has a number of advantages:</p>
<A NAME="TI3239"></A><p><A NAME="TI3240"></A>
<ul>
<li class=fi>When you change an ancestor object,
the changes are reflected in all the descendants. You do not have
to make manual changes in the descendants, as you would in a copy.
This saves you coding time and makes the application easier to maintain.</li>
<li class=ds>The descendant inherits the ancestor's
scripts, so you do not have to re-enter the code to add to the script.</li>
<li class=ds>You gain consistency in the code and objects in
your applications.
</li>
</ul>
</p>
<A NAME="TI3241"></A><p>This chapter describes how inheritance works in PowerBuilder
and how to use it to maximize your productivity.</p>
<p><img src="images/note.gif" width=17 height=17 border=0 align="bottom" alt="Note"> <span class=shaded>Opening ancestors and descendants</span> <A NAME="TI3242"></A>To enforce consistency, PowerBuilder does not let you open
an ancestor object until you have closed any descendants that are
open, or open a descendent object when its ancestor is open.</p>

